About.Ag Review of Sigma Metalytics Precious Metal Verifier
SummaryIt is a convenient tool, very fast, non-destructive, reads through plastic and easily detects many fakes... but cannot detect all fakes, and is very expensive.
My hope had been to order one, review it, praise it, and maybe help offset the cost of this site with some sales. I have quite a few fake/counterfeit pieces of metal to test with. Unfortunately, for most people, I cannot recommend this. It is a great tool, just much too expensive for the average user to justify. I would say the cost wouldn't likely make sense for people with less than perhaps $50K-$100K or so of metal (or less, if not from reputable sources).
DetailsI've heard about the Sigma Metalytics Precious Metal Verifier for a few years. Despite its odd claim ("Inexpensive to buy and use"), it is more expensive than just about any other precious metals tester other than XRF. But, it is very fast, non-destructive, and you often do not even need to take metal out of its coin holder or slab.
The catch is that it cannot detect all fake coins and bars. Their website does allow for this possibility, although they do downplay it.
The good news is that I did not find any false positives (coins or bars that were real, but showed as outside the expected range). I thought I did with some 1/10 ounce platinum coins, but they were simply too thin to be tested properly. Some did appear to be false positives, but were due to an error on my end (e.g. testing for .999 fine gold instead of .9167).
The tool works by testing the electrical resistivity of a piece of metal, and comparing it to known values for the metal you are testing, and showing a graphical representation to let you know if the metal is within the expected range, close to it, or outside of the expected range. Silver, for example, has a resistivity of about 1.6x10-8 ohm-meters, while gold has a resisitivity of about 2.3x10-8 ohm-meters. Lead, however, has a resistivity of about 21.3x10-8 ohm-meters.
So if you have gold-plated lead, the verifier might (internally) get a reading of 21.3, see that it is nowhere near the expected 2.3, and show that the reading is outside of the expected range. You can then be almost certain that what you have isn't real gold.
Sensors/WandsOne thing to be aware of is that the Sigma Metalytics Precious Metal Verifier can test metal either using the built-in sensor, or one of 3 optional "wands" (small, large, bullion).
However, you need to be careful to use an appropriate wand for the situation. Depending on the diameter/width, thickness, and type of metal, you may be limited in which sensor(s) you can use. There is a chart that lets you determine the best sensor(s) to use.
I would recommend getting all 3 wands when you order. For the (fairly) small price difference, it is worth having wands to handle any type of metal. The small wand can handle 1 gram silver bars, whereas the large wand can handle large bars.
The Problem - False NegativesA false negative is when the Sigma Metalytics Precious Metal Verifier tests a fake piece of metal, but the results show as within the expected range. Of 33 fake pieces I tested for this review, the Sigma Metalytics device correctly reported 31 of them as fake (outside of the bracketed expected range). That's very good, but not perfect - and hence why you need to also weigh/measure the metal. Sigma is quite clear that they do not recommend that the detector be the sole means of testing metal.
One of the first pieces of metal I tested was a copper bar (not included in this review, as it isn't fake). I set the Sigma Metalytics Precious Metal Verifier to "Silver-99.9% Pure", and tested the bar. It tested near dead-center, meaning that the bar was within the expected range for silver. For copper, weighing and measuring the bar will quickly determine that it is not silver, so this is not an issue *if* you weight and measure your silver. But a fake silver piece made of copper would very likely test as real.
However, I have some counterfeit pieces of metal (mostly gold) that passed this test. I believe all of them are easily detectable as fake by weighing and measuring them, but it shows that you cannot assume that because a piece of metal passed the Sigma test it is real.
Sample Test Results of Fake Metal
1. For "Results", -999 means a FAIL with an arrow pointing left, -6 through -3 means outside of the expected range (on the left side), -2 through 2 means within the expected range, 3 through 6 means outside of the expected range (on the right side), and 999 means a FAIL with an arrow pointing right.
ConclusionOverall, this is a terrific device.
The main problem is the price. For most small investors, it is prohibitively expensive. The other catch is that while it catches lots of fake metal, it doesn't detect it all. That's not a problem with the device itself, just an inherent drawback with the technology that it uses.
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